package cn.jinjie.day09;

import java.util.HashMap;

public class Test01 {
    public static void main(String[] args) {
        HashMap<String, String> map = new HashMap<>();
        map.put("001", "坏数字");
        map.put("002", "好数字");
        map.put("003", "黑马树哥");
        map.put("004", "黑马树哥1");
        System.out.println(map);
        System.out.println(map.containsKey("004"));
        map.remove("004");
        System.out.println(map.containsKey("004"));
        System.out.println(map.size());
        System.out.println(map.isEmpty());
        map.clear();
        System.out.println(map.isEmpty());

    }
}
